58=y2

Solution for 58=y2 equation:

58=y2

We move all terms to the left:

58-(y2)=0

We add all the numbers together, and all the variables

-1y^2+58=0

a = -1; b = 0; c = +58;
Δ = b2-4ac
Δ = 02-4·(-1)·58
Δ = 232
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{232}=\sqrt{4*58}=\sqrt{4}*\sqrt{58}=2\sqrt{58}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2\sqrt{58}}{2*-1}=\frac{0-2\sqrt{58}}{-2}
=-\frac{2\sqrt{58}}{-2}
=-\frac{\sqrt{58}}{-1}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2\sqrt{58}}{2*-1}=\frac{0+2\sqrt{58}}{-2}
=\frac{2\sqrt{58}}{-2}
=\frac{\sqrt{58}}{-1}
$